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Sep 10, 2018, 09:05 PM
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Build Log

Ta-183 Huckebein


Build night at Tom's (TRISME) always pumps up my enthusiasm and motivation so I decided to start a build thread on a plane I've wanted to build for a while, the TA-183. I really like the lines of this plane but it is a bit fat for me (hey, I like them thin!) so mine will go on a diet. I've found two threads on building a TA-183 slope plane; here,

https://www.rcgroups.com/forums/show...n#post14197080

and here,

https://www.rcgroups.com/forums/show...ld#post6880580


Both threads stopped at some point during the build (not sure why) but I managed to learn some do's and don'ts from them. I hope I manage to finish this build and eventually (the key word here) get the plane in the air!

The goal for me is to keep the look of the TA-183 but to address some of the issues/comments that were brought up in the previous build threads and to make it thinner.

My approach to the build will be much like the P-51 build I did last year; namely cut a foam fuse using a hotwire CNC and GCode generated by DevFus Foam and use that as a 'mold'. I found a 3 view of the TA-183 on the net and extracted some formers to input into DevFus Foam, this helps with the contouring of the fuse. I also get scaling factors from the 3 view, which is shown in pic #1 (I think this is a cleaned up version of the Luft46 3-view). All measurements and scaling is done using GIMP.

Since I really haven't seen a build log on a TA-183 slope plane built from scratch and fly, as an exercise I compared the TA-183 to a Mig-15 and an F-86 which are similar for well known reasons. This was done to give me some guidelines since I know the F-86 as a scaled slope plane flies well enough (ISR F-86 build, for example) and I guess the Mig does also (although I haven't found completed scratch built Mig slope planes). Pics #2 and #3 show sections taken from 3-view versions of the planes placed side by side with the planes scaled to the same wingspan measured perpendicular to the fuse centerline. In pic #2 the topviews are lined up so the LE at the fuse is a straight line. It's interesting for me to note that the length from the LE to the TE of the horizontal are all very similar. The main difference in length for the TA-183 is in the nose. Pic #3 shows the unscaled F-86 and Mig-15 fuse and tail-feathers along with the scaled to 70% TA-183 fuse and unscaled tail-feathers. (Man the Mig's vertical looks big!). It
seems clear the TA-183 should have a larger v-tail section and the vertical should be somewhere between the F-86's and the Mig's.

One thing I noticed was that because of the larger TE sweep (by ~ 10 degrees) of the TA-183 the tip of the wing ends up almost in line with the v-tail LE at the root, the F-86 and Mig's tips do not. I don't know enough about this to know if it is a concern. Can anyone elaborate?

Basically I won't change the scaling along the length of the fuselage but I will scale down the height and width of the fuse to about 70% of scale. This preserves the aspect ratio but makes the fuse much less fat. It also brings the tail surfaces down closer to the wing but decreases the surface area of the vertical which I will try to recover by making the width of the vertical larger. The wing geometry will remain as scale although I might decrease the sweep angle from 40 to 35 degrees. The v-tail surface area will be increased by about 30-40% over scale (very small surface and there is about 16 degrees dihedral to boot) by increasing the root chord, the tail span and decreasing the sweep angle some, maybe by 5 degrees.

Here are some initial parameters I decided on but can be changed since I haven't started cutting foam yet:

Half wingspan measured perpendicular to the centerline of the fuse: 20"
Root chord: ~ 10.5"
Tip chord: ~ 7.75"

Airfoil: I guess I'll go with an RG-14 with 3-4 degrees of washout (worked well for TFLG on several swept wing planes). I'm open to suggestions if anyone wants to chime in on this (can of worms just got opened?).

Overall length of the fuse: 34" This is divided into two sections, the main fuse at ~ 24" and the vertical which extends another ~ 10" at an angle of ~23% relative to the top part of the fuselage (the scale angle is ~ 31 degrees).
Width of fuse: 3.4" (scale is close to 5.1")
Height: ~5.1" (scale is ~ 7.9").

V-tail:
I will increase the root chord from ~ 4.75" to between 5.5" and 5.75". The half length span will be increased from 5.25" to between 6.25" and 6.5" and the sweep angle might be decreased by ~ 5 degrees. I will keep the dihedral. I will likely use an NACA0008 for the airfoil.


Vertical:
I will add ~ 1.5 inch length to the vertical, this will almost completely make up for the decrease in height from the scaling down to ~ 70% of scale. If I can I will try to add some more area to the vertical. The ratio of the width of the fuse to the vertical is ~ 5 to 1. Once I finish deciding on the root chord for the vertical then the ratio will help me decide on the airfoil thickness to cut so the vertical looks scale in thickness (can't make it too small in thickness because the torque rod / clevis system has to fit in).

Pic #4 shows the formers for the fuse and pics #5 and 6 show some 3D views from DevFus Foam with formers in place and the contouring done. You can see there are 6 blocks to cut (actually 12, I cut left and right halves separately) and I will extend the last block on the right about 1.5 inches to add length to the vertical tail surface. You can also see that the cuts don't follow the contours of the nose or canopy very well (straight wire CNC cut). I usually cut a bit larger than the boundary and then sand the final shape.
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Sep 10, 2018, 09:05 PM
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Sep 11, 2018, 08:04 PM
It's not going to build itself
TRISME's Avatar
I didn't even know that there was a TA-183. That looks like quite the project, I would look at similar builds and see what they did for sure. I will be watching and learning.
Tom
Sep 11, 2018, 08:15 PM
IT'S NOSE HEAVY!!!!
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Sep 11, 2018, 08:41 PM
Living the dream
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Sep 11, 2018, 08:51 PM
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Neat!
Sep 30, 2018, 08:04 PM
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Warning, another long winded post (but this should be the last long winded one I make during the build log, really).

Just for some amusement I did a few more calculations to see what the horizontal and vertical volume coefficients were for the Ta-183 (scale and also 'squished' by 70%) compared to the scale Mig-15 and F-86. From my reading, guidelines seem to indicate Vh > 0.3 and Vv > 0.02. I did not change any of the plane's planform. For input numbers into the cg calculator (used one that gives horizontal volume coefficient and wing area) I choose what I will build, a 20" half wingspan.

F-86
Vh ~ 0.28
Vv~ 0.035
Wing Area: 326 sq.in

Mig-15
Vh~ 0.37
Vv~ 0.07
Wing Area: 308 sq.in

Ta-183
(Scale) Vh~ 0.2 (very small horizontal tail feathers)
(Scale) Vv~ 0.032

'Squished' 70% version:
Vh ~ 0.35 [Add 1.5 inches to the horizontal root and increase the half-span from 5.2" to 7" while keeping the sweep angles as scale.]
Vv~ 0.028 [Extended vertical width by ~ 2 inches]
Wing Area: 355 sq.in

I added about 2 inches to the rear of the fuselage to accommodate the additional length of the vertical so Vv would be acceptable. I also added another former near the nose and at the rear which gives a closer to scale contour. This was also necessary since my trial cuts yielded poor results because the perimeters at the ends of the block were very different and this caused cutting problems. Breaking the blocks up into two parts resulted in reasonable cuts. The CAD pic is shown below.

Due to this additional length the fuselage dimensions change some. Now I have:

Fuse length: 36.25"
Fuse width: 3.6"
Fuse height (to top of canopy): 5.6"


The foam blocks pushed together are shown in a pic below. Block to block there is some variation in height but this is very easily fixed. The vertical was cut using a NACA0008 airfoil but seems too thin to me. I think I will recut a vertical and use a NACA0012 or NACA0014 airfoil.
Oct 01, 2018, 05:29 AM
Registered User
Designers of freeflight scale planes tend to enlarge the tailfeathers by 10%-ish quite often for these reasons.
Last edited by Cap_n_Dave; Oct 01, 2018 at 05:47 AM.
Oct 01, 2018, 06:49 AM
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_AL_'s Avatar
I love the 183 but it's one of those designs that might fly ok, or might be bloody awful.
It's looking good so far & I'll be watching closely.

Al
Oct 01, 2018, 07:58 AM
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TFLG's Avatar
There were quite a few electric kits of this about 10 years back and "bloody awful" was how many of them flew. I don't recall the problems but a lot of guys had trouble getting them to fly. My guess is the CG will be way back and close to the tail making it essentially very short coupled. The high mounted stab and anhedral will add to the squirrely equation especially at low speed. I nearly built one but went with the Me.P1101 instead. That one actually flew quite well and I still have it hanging in the Cave of Wonders.

https://static.rcgroups.net/forums/a...4-Pict0025.jpg
Oct 01, 2018, 11:45 PM
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Thread OP
Quote:
Originally Posted by _AL_
I love the 183 but it's one of those designs that might fly ok, or might be bloody awful.
It's looking good so far & I'll be watching closely.

Al
Al,
I really like the 183 also. I don't know why it was called huckebein after the unlucky raven (maybe because it might fly 'bloody awful'). Anyway, it always looked like a fat swallow to me, except for the wing tips.

Eusebio
Oct 01, 2018, 11:58 PM
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Thread OP
Quote:
Originally Posted by TFLG
There were quite a few electric kits of this about 10 years back and "bloody awful" was how many of them flew. I don't recall the problems but a lot of guys had trouble getting them to fly. My guess is the CG will be way back and close to the tail making it essentially very short coupled. The high mounted stab and anhedral will add to the squirrely equation especially at low speed. I nearly built one but went with the Me.P1101 instead. That one actually flew quite well and I still have it hanging in the Cave of Wonders.

https://static.rcgroups.net/forums/a...4-Pict0025.jpg
The Wizard has returned from the Land of Oz(zies), welcome back. Somehow I missed the Me. P1101 when I visited the Cave of Wonders, maybe next time. I have seen videos of it flying though and it does seem to fly nicely...

You made similar comments in one of the Ta-183 build threads I referenced above. Your comments were the reason I did my little scaling exercise. If you look at the 2nd pic in the OP you can see that the distance between the leading edge (LE) of the wing and LE of the horizontal stab are almost identical for the 3 planes, the F-86, Mig-15 and the Ta-183. If you go to a CG calculator and put in each plane's planform (neglecting stab dimensions) you will see that the CG for the F-86, e.g., is just 1 inch closer to the wing LE than the case of the Ta-183. Therefore, the 'moment arm' for each is quite similar (I am neglecting details of the stab planform but they are all similar--a more detailed look doesn't really change the results much). The reason for the small Vh of the Ta-183 seems to be the small projected tail surface area (and there is also the fact that the surface area of the Ta-183 wing is 'big' because of the larger trailing edge sweep, it is ~ 15% greater than the F-86 e.g.). The new dimensions I've chosen for the stab now result in a Vh of ~ 0.35 or so which I guess should be sufficient (stab area is almost 20% of the wing area).

If you look at pic 3 of the OP you will see that the high mounted stab is actually no longer so highly mounted (bottom row of figures) once you squish down the vertical dimensions to 70% of scale. It is about the same as the Mig's from the fuse centerline but is 3 times higher than that of the F-86. It seems to me, though, that a better measure is how high from the wing LE centerline the stab is and then it is just 30% greater than that of the F-86 and ~ 65% less than that of the Mig.

Anhedral? I don't need no stinkin' anhedral! I'm going with design II from Luft'46 which, to my eye, doesn't have any anhedral in the wing.
Last edited by ek123; Oct 02, 2018 at 12:48 PM.
Oct 02, 2018, 08:42 AM
Crafter of flying plugs
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Oct 02, 2018, 04:24 PM
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Here's a little video Carlski shot of my Me-P1101 at soar utah. It's a little boring as some of the manouvers were required as part of a scale judging flight.

(5 min 32 sec)
Oct 02, 2018, 08:26 PM
It's not going to build itself
TRISME's Avatar
Nice footage!
There's also some footage in PSS Masters. I'll put it on the monitor at build night this Thursday


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